Elderly patients will increasingly undergo cardiac surgery as the general population of elderly patients with heart disease increases each year. Age is an incremental risk factor for surgical complications in patients who have coronary artery bypass graft (CABG) surgery, especially central nervous system complications. Elderly patients appear to be especially at increased risk of suffering cognitive and neuropsychologic dysfunction postoperatively. The mechanism by which this occurs is not known. We propose to assess the impact of postoperative cognitive and neuropsychologic dysfunction on short and long-term quality of life in cardiac surgical patients. The incidence and severity of neuropsychologic dysfunction will be determined by neurologic and psychometric testing in 100 CABG patients over one year, with a control group of 50 angioplasty patients used as a reference of change in quality of life with improvement in disease state. The duration of cognitive dysfunction will be determined by serial testing. A comprehensive neuropsychological test battery will be administered on the day before surgery, 6 weeks and 6 months post-CABG. An extensive quality of life battery designed to assess aspects of generic and disease specific quality of life will be administered at the same testing periods. Simultaneous assessment will allow us to determine cognitive decline and its association with changes in quality of life. Cardiopulmonary bypass (CPB) is an excellent model for the study of neuropsychologic dysfunction since a relatively high incidence of events can be expected. The new knowledge generated in this investigation could lead to a better understanding of cognitive decline and its importance to quality of life after cardiac surgery in the elderly. This data will allow us for the first time to determine the importance of proceeding with potential pharmacologic, temperature or CPB technology interventions to reduce neuropsychologic deficits after cardiac surgery in the elderly.